package com.example.express.mvc;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class DispatcherServlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String uri = req.getRequestURI();
        HandleMapping.MVCMapping mvcMapping = HandleMapping.get(uri);
        if (mvcMapping == null){
            resp.sendError(404,"MVC映射地址不存在:"+uri);
            return;
        }
        Object object = mvcMapping.getObject();
        Method method = mvcMapping.getMethod();
        Object result = null;
        try {
            result = method.invoke(object,req,resp);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        switch (mvcMapping.getType()){
            case TEXT:
                resp.getWriter().write((String) result);
                break;
            case VIEW:
                resp.sendRedirect((String) result);
                break;
        }
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        String path = config.getInitParameter("contentConfigLocation");
        InputStream resourceAsStream = DispatcherServlet.class.getClassLoader().getResourceAsStream(path);
        HandleMapping.load(resourceAsStream);
    }
}
